The present invention is related to a previously developed high speed axial flow carbon dioxide gas laser generator or oscillator. A high speed axial flow carbon dioxide gas laser generator or oscillator comprises, a laser generator section supported on a supporting frame, an attachment which adjusts the laser generator section, a main heat exchanger for cooling the laser gas (a mixed gas of carbon dioxide, nitrogen and helium), a gas circulation drive device for circulating the laser gas provided on the top surface of the main heat exchanger 11, and an auxiliary heat exchanger 15 provided on the top section of the gas circulation drive device.
The laser generating section comprises two groups of laser tubes freely movable in micromotion in the lateral direction.
The present invention relates to a device for monitoring the discharge voltage in the shells of the laser tubes.
The laser tubes are formed from a pair of central shells and a pair of end shells respectively. In these shells, positive electrodes and negative electrodes are provided for discharge, and the discharge is performed by an AC power source at the respective locations. The positive electrodes of the neighboring laser tubes (central shells) and (end shells) are connected to the positive sides of each of a plurality of separately provided variable DC power sources and grounded therewith E. The negative electrodes are provided adjacent to a discharge section, and each is respectively connected to the negative side of the DC power source through a ballast resistance.
The laser gas is placed in a state of excitation by a discharge between these pairs of electrodes, and the excitation light passes to a rear mirror, then to a plurality of bend mirrors, and returns to an output mirror. This excitation light is amplified and produces the laser oscillation. One part of this oscillation is directed externally by the output mirror 45 and is used for laser processing.
In the discharge circuit, a plurality of discharge voltage monitors monitor the voltage at the negative electrodes through a plurality of detector resistances in order to monitor the discharge status of each of the laser tubes. This type of discharge voltage monitor is provided because the electrical resistances between the two negative electrodes of the laser tubes differ in the respective laser tubes, and when the difference in electric potential becomes large, a discharge is produced between the two negative electrodes so that the laser oscillation becomes unstable, causing the output to drop, which must be prevented.
This discharge voltage monitoring device detects and indicates the negative electrode voltage of each of the laser tubes respectively. When the difference between these voltages is large, a specified operation is carried out, either by an operator, or automatically. However, when a discharge is produced between two negative electrodes for example, the electric potential between the two negative electrodes will change to become smaller. In such a case, it is not possible to conclude from the monitor indication that there is an abnormality. Accordingly, this discharge voltage monitoring device will not necessarily indicate clearly the discharge status of the laser tube.